Abstract

This paper describes a four-step methodology developed to quantify the benefits of advanced hydraulic fracturing techniques. Three case studies illustrate application of this methodology in a variety of study sizes to quantify the benefits of fracture treatment optimization, fracture treatment quality control, and on-site fracture treatment diagnostics and real-time analysis. These benefits result from increased production, completion/stimulation cost savings, or some combination of both. Benefit-To-Cost ratios are 3:1 to 5:1, and the largest study indicates the technology benefits may be derived from as few as 10% to 20% of the technology application wells. Technology benefits are sometimes location dependent: a specific technology may be significantly beneficial in one area but not cost effective in another area of the same field. This paper outlines the documentation of $19 million in benefits on 105 AST wells.

Introduction

Over the last several years, the Gas Research Institute (GRI) has undertaken a technology transfer deployment program known as "Advanced Stimulation Technologies" (AST). The goal of this program has been to transfer existing stimulation related technologies developed in part by the GRI to gas producers in the United States. As part of this deployment program, gas producers, in cooperation with GRI deployment contractors, select candidate wells, design the optimal fracture treatment using advanced technologies, implement the treatments in the field, and quantify the benefits of the technology application. The intent of the program is to provide the producer with sufficient training to allow continued use of the technologies in the future without involvement from the GRI contractor. An integral part of this training is the application of benefits analyses for technology application justification. Without the realistic documentation of AST benefits, the continued application of AST or other technologies by the producer may not occur. The AST approach represents a process for optimizing hydraulic fracturing results. Key steps in the process include pre-fracture evaluation, stress profiling, treatment design using 3-D fracture models, real-time fracture treatment analysis, fracture fluid quality control, and post-fracture evaluation. The real-time data collection and analysis enables on-site evaluation of fluid efficiency, near-wellbore entry friction, and net pressure, both prior to and during the fracture treatment. Changes in the fracture treatment can be made to alleviate problems and optimally place the proppant in the fracture.

The purpose of this paper is to present a general benefits evaluation procedure for calculating stimulation technology benefits and to show how this procedure was used in three separate AST deployments. The benefits procedure includes construction of a base-line production estimate using average offset well performance, a theoretical production improvement given application of the advanced stimulation technologies, and a post-mortem evaluation using actual production data. The first case study illustrates the application of the benefits methodology to 80 AST wells with 146 offsets. This case represents a high quality dataset for this type of analysis. Case two shows the problems associated with benefits analysis when very little offset data are available. The benefits analysis was attempted on 22 AST wells; a complete benefits analysis was only possible on two of the 22 wells. The final case study shows the benefits methodology applied to a three well AST program where excellent offset data were available.

Evaluating technology benefits is often difficult because the incremental boost in production derived from the technology application is typically smaller than production variations due to local changes in permeability-thickness or reservoir pressure. Depletion or locally poor permeability often mask a successful technology deployment. Conversely, drilling a well in a local sweet spot may result in high production volumes that are incorrectly attributed to an unsuccessful technology application. To overcome this problem, the benefits evaluation procedure considers the local production performance around the well and recognizes that a fair amount of production variability from well-to-well is likely due to rock quality changes. P. 19^

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